Versions and changes

Every steam locomotive undergoes changes over its lifetime. Most changes are made for operational reasons especially at the start of a class's life. As units of a class are put to work teething problems have to be worked out and the design is gradually adapted for more efficient working. As the age of the class increases mechanical problems show up, inferior materials give way, wear and fatigue sets in and cracks appear due to unexpected and/or uncorrected stresses. Changes are also made due to changing safety regulations or new railway standards. Finally another source of change can be found in the way and the area locomotives are worked.

The AD60 was no exception. On this page you will find the most important changes I have been able to trace by reading books, studying photos etc. I did some of the research so why not share it with you. If you want to model a locomotive in a specific time frame you should observe these changes. I will try to document those changes which had a significant impact on the appearance of the machines and thus need to be modelled. I do not pretend to be complete, constructional changes on a complex machine as an AD60 run into the thousands, big and small. If you have a question, a comment or even better an addition or correction, please contact me.

The 6040 marked as "heavy" .
Oddly the book "The 60 Class" marks it as a light Garratt

Axle load

First and most important is the fact that there where two subclasses of the AD60, the "light" and the "heavy" 60's. All engines where supplied as "light" engines. All coupled axles carried a 16 ton axle load and the carrying axles took up 16 tons each. As it turned out the AD60 was rarely put to work on the railroads for which this relatively low axle load was intended. So the springing of the loco was rearranged to load 14 tons on the carrying axles and increase the axle load of the coupled axles to 18 tons, raising the tractive effort from about 27 tons to 29 tons.

"Heavy" AD60s where marked with two + signs behind the road number.

The change was implemented from 1958 to 1960

Road numbers 6003-6005, 6011-6014, 6020, 6038, 6040 remained "light" AD60s.

At the same time these locomotive's cylinders where bored out to a larger size but as far as I can establish this had no impact on the visual appearance of the loco (but please correct me if I'm wrong)

Sound pipes

The AD60 were noisy boys and the crews had difficulty to hear detonators. These detonators where placed on the track to protect a train in trouble further down the line, so danger was ahead. Not hearing the detonators explode under the leading wheels could result in accidents. To this end the sound pipes, or sound intensifiers, where added starting with no 6007 in December 1958

Jacks

The 60s where originally supplied with two sets of jacks, one set placed on the foot plate of each unit. Around 1960 all these jacks where gone.

Air vents

The first batch of AD60s (6001-6025) we delivered with the air vents set wide apart on the rear of the front tanks. Before long however they were moved forward and placed close together. The second (6026-6042) already had this modification upon delivery

Brakes

As built the loco only had brakes on the drivers. To increase the locomotive's braking power, the bogies were later provided with additional brake rigging.

No photo available. See page 23 of  "The 60 Class" by Ken Groves for two types of fire hole doors

Cab interior

A very small detail barely worth bothering is the fire hole door. Beyer Peacock supplied the loco with the standard swing out fire hole door, but these were soon replaced with butterfly type fire hole doors.

The thirty odd AD60s that became "heavy" were mostly also fitted with dual controls to allow driver and fireman swap positions in the cab to while driving bunker first.

Note:

I cannot trace the origins of the photos on this page anymore. Please contact me if you feel I have done anything wrong.